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Concentration-Dependent Double-Step Transition of the Diffusion Coefficient in Dilute Solutions of Styrene-Butadiene Diblock Copolymer in Selective Solvent

  • Y. Tsunashima
Conference paper
Part of the Springer Proceedings in Physics book series (SPPHY, volume 52)

Abstract

A poly(styrene)-block-poly(butadiene) copolymer dissolved in n-decane exibits a double-step transition in the diffusion coefficient D(c) at the extremely dilute polymer concentration ranging from l×10-6 to 7.24×10-3 gcm-3 at 25°C. The copolymer disperses monomolecularly only in the extremely dilute solution region limited to c<c1 with c1 = 3.8×10-6 gcm-3. At c>c1 (first onset concentration), micellization of some kind occurs due to the strong attractive interaction between polystyrene (PS) subchains, the copolymers associating intermolecularly. The micelle is huge and nearly monodisperse in size and is constructed from loose packing of PS subchains. At c>c2 (second onset concentration with c2 = 1.1×10-4 gcm-3), the PS subchains collapse into a hard and compact core, while the polybutadiene (PB) subchains swell well and cover the core, forming approximately a “two-phase” concentric sphere. This micelle exibits an internal motion which may be caused by the concentration fluctuation of the highly extended PB chains relative to the hard core of PS chains.

Keywords

Diblock Copolymer Microphase Separation Concentric Sphere Loose Packing Selective Solvent 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Springer-Verlag Berlin Heidelberg 1990

Authors and Affiliations

  • Y. Tsunashima
    • 1
  1. 1.Institute of Chemical ResearchKyoto UniversityUji, Kyoto-fu 611Japan

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